Lidar Sensor System with Improved Optical Isolation Features

Light Detection and Ranging (LIDAR) systems use lasers to create three-dimensional representations of surrounding environments. A LIDAR system includes at least one emitter paired with a receiver to form a channel, though an array of channels may be used to expand the field of view of the LIDAR system. During operation, each channel emits a laser beam into the environment. The laser beam reflects off of an object within the surrounding environment, and the reflected laser beam is detected by the receiver. A single channel provides a single point of ranging information. Collectively, channels are combined to create a point cloud that corresponds to a three-dimensional representation of the surrounding environment.

The emitter and/or receiver often includes photonic circuitry formed on a semiconductor substrate such as a silicon die. Silicon photonics dies can provide for precise formation of the photonic circuitry through, for example, photolithography. Other optical components of a LIDAR sensor system may also be formed on semiconductor substrates, while still others are formed on or connected to components made using other semiconductor materials such as, for example, a group III-V semiconductor, gallium arsenide (GaAs), and/or other suitable materials.

Aspects and advantages of implementations of the present disclosure will be set forth in part in the following description, or may be learned from the description, or may be learned through practice of the implementations.

Example aspects of the present disclosure are directed to LIDAR systems. As further described herein, the LIDAR systems can be used by various devices and platforms (e.g., robotic platforms, etc.) to improve the ability of the devices and platforms to perceive their environment and perform functions in response thereto (e.g., autonomously navigating through the environment).

A LIDAR system may include one or more photodetectors to convert reflected light to a signal that can be processed for detection by the LIDAR system (e.g., an electrical signal or optical signal). Light can enter the environment surrounding a photodetector (e.g., internal to the LIDAR system) from various sources, such as misaligned couplings and other leakages. This stray light can be picked up by the photodetector and cause reduced detection accuracy. The present disclosure provides for LIDAR sensor systems having improved optical isolation features. These optical isolation features can provide improved optical isolation within the LIDAR sensor system. For instance, the optical isolation features can reduce an amount of stray light incident on photodetector(s) and other light-sensitive devices within the LIDAR sensor system, thereby providing improved detection fidelity and accuracy. In particular, the present disclosure provides for forming optical isolation trenches, including airgap trenches and filled trenches, with particular spatial relationships to a light-sensitive device (e.g., a photodetector). Forming the trenches can be accomplished through various techniques, such as etching (e.g., dry etching, wet etching), ablation, (e.g., laser ablation), cutting, or other suitable techniques.

The arrangement of the optical isolation trenches relative to the light-sensitive device can be such that the trenches absorb, block, or reflect (by total internal reflection) stray light that may otherwise be incident on the light-sensitive device. As one example, a substrate can include a first side (e.g., having an SiO2 layer) opposite a second side (e.g., having a silicon layer). The light-sensitive device can be on or embedded within the first side. One example trench is formed on the first side. The trench may extend a depth into the substrate. The depth may be less than about half of a total thickness of the substrate. The trench may be an airgap trench (e.g., filled with air, or alternatively a vacuum or other substance immediately surrounding the substrate), or a filled trench filled with some light-absorbing material, such as a metal or a fluid including carbon nanoparticles dispersed in nitrocellulose. Another example trench is formed on the second side. This trench may extend a particular depth into the substrate, and the depth may be any suitable depth, up to almost an entirety of the silicon layer. In another approach, the trenches may undercut the light-sensitive device to form a cavity beneath the light-sensitive device. The cavity may be filled with optically absorbing material to optically isolate the device from stray light. As another example, a substrate can include a first end and a second end, with trenches formed on each end. The light-sensitive device(s), such as photodiodes, can be positioned between the two ends. The trenches can prevent a direct path for light through the receiver die.

Aspects of the present disclosure can provide a number of technical effects and benefits. As one example, including one or more optical isolation trenches relative to a light-sensitive device can provide for a reduced amount of stray light incident on the light-sensitive device. The reduced amount of stray light can, in turn, provide for improved fidelity of detections from the light-sensitive device, due at least in part to the reduced amount of stray light in competition with intended light related to the detection. Additionally or alternatively, the reduced amount of stray light can provide for reduced power consumption of a LIDAR sensor system incorporating these aspects. For instance, the reduced amount of stray light in competition with the intended light can provide for use of a lesser optical signal to drive the LIDAR sensor system, requiring less power to generate the optical signal than in a comparable LIDAR sensor system not including the aspects of the present disclosure.

For example, in an aspect, the present disclosure provides a light detection and ranging (LIDAR) system. The LIDAR system includes a substrate having a first side and a second side. The LIDAR system includes a light-sensitive device arranged on the first side of the substrate. The LIDAR system includes one or more optical isolation trenches formed into the substrate, the optical isolation trenches configured to optically isolate the light-sensitive device from light entering the substrate.

In some implementations, the substrate includes an oxide layer at the first side and a semiconductor layer at the second side.

In some implementations, the light-sensitive device is or includes a photodetector.

In some implementations, the one or more optical isolation trenches include an airgap trench, the airgap trench filled with a substance occupying an environment of the substrate.

In some implementations the one or more optical isolation trenches include a filled trench, the filled trench having a light-absorbing filling.

In some implementations, the light-absorbing filling includes a metal, a ceramic, an organic compound, or a suspension.

In some implementations, the light-absorbing filling is a fluid including carbon nanoparticles dispersed in nitrocellulose.

In some implementations, the one or more optical isolation trenches include at least one undercut trench forming a cavity in the substrate under the light-sensitive device, the cavity being filled with a light-absorbing filling.

In some implementations, the one or more optical isolation trenches are configured to optically isolate the light-sensitive device by reflecting light entering the substrate through total internal reflection.

In some implementations, the one or more optical isolation trenches include at least one blocking trench formed on the first side of the substrate.

In some implementations, the one or more optical isolation trenches include at least one blocking trench formed on the second side of the substrate.

In some implementations, a thickness and a depth of the one or more optical isolation trenches is less than about one half of the thickness of the substrate.

In some implementations, the depth of the one or more optical isolation trenches is between about 20 micrometers and about 300 micrometers.

In some implementations, the LIDAR system further includes an antireflection layer formed on the second side of the substrate.

For instance, in an aspect, the present disclosure provides an autonomous vehicle (AV) control system. The AV control system includes a light detection and ranging (LIDAR) system. The LIDAR system includes a substrate having a first side and a second side. The LIDAR system includes a light-sensitive device arranged on the first side of the substrate. The LIDAR system includes one or more optical isolation trenches formed into the substrate, the optical isolation trenches configured to optically isolate the light-sensitive device from light entering the substrate.

In some implementations, the substrate includes an oxide layer at the first side and a semiconductor layer at the second side.

In some implementations, the one or more optical isolation trenches include an airgap trench, the airgap trench filled with a substance occupying an environment of the substrate.

In some implementations, the one or more optical isolation trenches include a filled trench, the filled trench having a light-absorbing filling.

In some implementations, the one or more optical isolation trenches include at least one undercut trench forming a cavity in the substrate under the light-sensitive device, the cavity being filled with a light-absorbing filling.

For instance, in an aspect, the present disclosure provides an autonomous vehicle (AV). The AV includes a light detection and ranging (LIDAR) system. The LIDAR system includes a substrate having a first side and a second side. The LIDAR system includes a light-sensitive device arranged on the first side of the substrate. The LIDAR system includes one or more optical isolation trenches formed into the substrate, the optical isolation trenches configured to optically isolate the light-sensitive device from light entering the substrate.

Other example aspects of the present disclosure are directed to other systems, methods, apparatuses, tangible non-transitory computer-readable media, and devices for manufacturing semiconductor devices for a LIDAR system, as well as motion prediction and/or operation of a device (e.g., a vehicle) including a LIDAR system having a LIDAR module with one or more semiconductor devices according to example aspects of the present disclosure.

These and other features, aspects and advantages of various implementations of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate implementations of the present disclosure and, together with the description, serve to explain the related principles.

The following describes the technology of this disclosure within the context of an autonomous vehicle for example purposes only. As described herein, the technology is not limited to an autonomous vehicle and can be implemented within other robotic and computing systems as well as various devices. For example, the systems and methods disclosed herein can be implemented in a variety of ways including, but not limited to, a computer-implemented method, an autonomous vehicle system, an autonomous vehicle control system, a robotic platform system, a general robotic device control system, a computing device, etc.

1 5 FIG.-B 1 FIG. 100 100 100 101 102 100 101 108 110 101 112 104 110 101 130 140 150 160 130 140 150 160 101 101 With reference to, example implementations of the present disclosure are discussed in further detail.depicts a block diagram of an example autonomous vehicle control systemfor an autonomous vehicle according to some implementations of the present disclosure. The autonomous vehicle control systemcan be implemented by a computing system of an autonomous vehicle). The autonomous vehicle control systemcan include one or more sub-control systemsthat operate to obtain inputs from sensor(s)or other input devices of the autonomous vehicle control system. In some implementations, the sub-control system(s)can additionally obtain platform data(e.g., map data) from local or remote storage. The sub-control system(s)can generate control outputs for controlling the autonomous vehicle (e.g., through platform control devices, etc.) based on sensor data, map data, or other data. The sub-control systemmay include different subsystems for performing various autonomy operations. The subsystems may include a localization system, a perception system, a planning system, and a control system. The localization systemcan determine the location of the autonomous vehicle within its environment; the perception systemcan detect, classify, and track objects and actors in the environment; the planning systemcan determine a trajectory for the autonomous vehicle; and the control systemcan translate the trajectory into vehicle controls for controlling the autonomous vehicle. The sub-control system(s)can be implemented by one or more onboard computing system(s). The subsystems can include one or more processors and one or more memory devices. The one or more memory devices can store instructions executable by the one or more processors to cause the one or more processors to perform operations or functions associated with the subsystems. The computing resources of the sub-control system(s)can be shared among its subsystems, or a subsystem can have a set of dedicated computing resources.

100 100 104 110 100 In some implementations, the autonomous vehicle control systemcan be implemented for or by an autonomous vehicle (e.g., a ground-based autonomous vehicle). The autonomous vehicle control systemcan perform various processing techniques on inputs (e.g., the sensor data, the map data) to perceive and understand the vehicle's surrounding environment and generate an appropriate set of control outputs to implement a vehicle motion plan (e.g., including one or more trajectories) for traversing the vehicle's surrounding environment. In some implementations, an autonomous vehicle implementing the autonomous vehicle control systemcan drive, navigate, operate, etc. with minimal or no interaction from a human operator (e.g., driver, pilot, etc.).

In some implementations, the autonomous vehicle can be configured to operate in a plurality of operating modes. For instance, the autonomous vehicle can be configured to operate in a fully autonomous (e.g., self-driving, etc.) operating mode in which the autonomous platform is controllable without user input (e.g., can drive and navigate with no input from a human operator present in the autonomous vehicle or remote from the autonomous vehicle, etc.). The autonomous vehicle can operate in a semi-autonomous operating mode in which the autonomous vehicle can operate with some input from a human operator present in the autonomous vehicle (or a human operator that is remote from the autonomous platform). In some implementations, the autonomous vehicle can enter into a manual operating mode in which the autonomous vehicle is fully controllable by a human operator (e.g., human driver, etc.) and can be prohibited or disabled (e.g., temporary, permanently, etc.) from performing autonomous navigation (e.g., autonomous driving, etc.). The autonomous vehicle can be configured to operate in other modes such as, for example, park or sleep modes (e.g., for use between tasks such as waiting to provide a trip/service, recharging, etc.). In some implementations, the autonomous vehicle can implement vehicle operating assistance technology (e.g., collision mitigation system, power assist steering, etc.), for example, to help assist the human operator of the autonomous platform (e.g., while in a manual mode, etc.).

100 102 104 106 108 112 100 The autonomous vehicle control systemcan be located onboard (e.g., on or within) an autonomous vehicle and can be configured to operate the autonomous vehicle in various environments. The environment may be a real-world environment or a simulated environment. In some implementations, one or more simulation computing devices can simulate one or more of: the sensors, the sensor data, communication interface(s), the platform data, or the platform control devicesfor simulating operation of the autonomous vehicle control system.

101 106 106 106 In some implementations, the sub-control system(s)can communicate with one or more networks or other systems with communication interface(s). The communication interface(s)can include any suitable components for interfacing with one or more network(s), including, for example, transmitters, receivers, ports, controllers, antennas, or other suitable components that can help facilitate communication. In some implementations, the communication interface(s)can include a plurality of components (e.g., antennas, transmitters, or receivers, etc.) that allow it to implement and utilize various communication techniques (e.g., multiple-input, multiple-output (MIMO) technology, etc.).

101 106 101 106 110 106 130 140 150 160 In some implementations, the sub-control system(s)can use the communication interface(s)to communicate with one or more computing devices that are remote from the autonomous vehicle over one or more network(s). For instance, in some examples, one or more inputs, data, or functionalities of the sub-control system(s)can be supplemented or substituted by a remote system communicating over the communication interface(s). For instance, in some implementations, the map datacan be downloaded over a network to a remote system using the communication interface(s). In some examples, one or more of the localization system, the perception system, the planning system, or the control systemcan be updated, influenced, nudged, communicated with, etc. by a remote system for assistance, maintenance, situational response override, management, etc.

102 102 102 102 102 102 102 102 102 The sensor(s)can be located onboard the autonomous platform. In some implementations, the sensor(s)can include one or more types of sensor(s). For instance, one or more sensors can include image capturing device(s) (e.g., visible spectrum cameras, infrared cameras, etc.). Additionally or alternatively, the sensor(s)can include one or more depth capturing device(s). For example, the sensor(s)can include one or more LIDAR sensor(s) or Radio Detection and Ranging (RADAR) sensor(s). The sensor(s)can be configured to generate point data descriptive of at least a portion of a three-hundred-and-sixty-degree view of the surrounding environment. The point data can be point cloud data (e.g., three-dimensional LIDAR point cloud data, RADAR point cloud data). In some implementations, one or more of the sensor(s)for capturing depth information can be fixed to a rotational device in order to rotate the sensor(s)about an axis. The sensor(s)can be rotated about the axis while capturing data in interval sector packets descriptive of different portions of a three-hundred-and-sixty-degree view of a surrounding environment of the autonomous platform. In some implementations, one or more of the sensor(s)for capturing depth information can be solid state.

102 104 104 101 101 104 104 101 104 104 102 104 104 The sensor(s)can be configured to capture the sensor dataindicating or otherwise being associated with at least a portion of the environment of the autonomous vehicle. The sensor datacan include image data (e.g., 2D camera data, video data, etc.), RADAR data, LIDAR data (e.g., 3D point cloud data, etc.), audio data, or other types of data. In some implementations, the sub-control system(s)can obtain input from additional types of sensors, such as inertial measurement units (IMUs), altimeters, inclinometers, odometry devices, location or positioning devices (e.g., GPS, compass), wheel encoders, or other types of sensors. In some implementations, the sub-control system(s)can obtain sensor dataassociated with particular component(s) or system(s) of the autonomous vehicle. This sensor datacan indicate, for example, wheel speed, component temperatures, steering angle, cargo or passenger status, etc. In some implementations, the sub-control system(s)can obtain sensor dataassociated with ambient conditions, such as environmental or weather conditions. In some implementations, the sensor datacan include multi-modal sensor data. The multi-modal sensor data can be obtained by at least two different types of sensor(s) (e.g., of the sensors) and can indicate static and/or dynamic object(s) or actor(s) within an environment of the autonomous vehicle. The multi-modal sensor data can include at least two types of sensor data (e.g., camera and LIDAR data). In some implementations, the autonomous vehicle can utilize the sensor datafor sensors that are remote from (e.g., offboard) the autonomous vehicle. This can include for example, sensor datacaptured by a different autonomous vehicle.

101 110 110 110 110 110 104 110 The sub-control system(s)can obtain the map dataassociated with an environment in which the autonomous vehicle was, is, or will be located. The map datacan provide information about an environment or a geographic area. For example, the map datacan provide information regarding the identity and location of different travel ways (e.g., roadways, etc.), travel way segments (e.g., road segments, etc.), buildings, or other items or objects (e.g., lampposts, crosswalks, curbs, etc.); the location and directions of boundaries or boundary markings (e.g., the location and direction of traffic lanes, parking lanes, turning lanes, bicycle lanes, other lanes, etc.); traffic control data (e.g., the location and instructions of signage, traffic lights, other traffic control devices, etc.); obstruction information (e.g., temporary or permanent blockages, etc.); event data (e.g., road closures/traffic rule alterations due to parades, concerts, sporting events, etc.); nominal vehicle path data (e.g., indicating an ideal vehicle path such as along the center of a certain lane, etc.); or any other map data that provides information that assists an autonomous vehicle in understanding its surrounding environment and its relationship thereto. In some implementations, the map datacan include high-definition map information. Additionally or alternatively, the map datacan include sparse map data (e.g., lane graphs, etc.). In some implementations, the sensor datacan be fused with or used to update the map datain real time.

101 130 130 101 The sub-control system(s)can include the localization system, which can provide an autonomous vehicle with an understanding of its location and orientation in an environment. In some examples, the localization systemcan support one or more other subsystems of the sub-control system(s), such as by providing a unified local reference frame for performing, e.g., perception operations, planning operations, or control operations.

130 130 130 101 106 In some implementations, the localization systemcan determine a current position of the autonomous vehicle. A current position can include a global position (e.g., respecting a georeferenced anchor, etc.) or relative position (e.g., respecting objects in the environment, etc.). The localization systemcan generally include or interface with any device or circuitry for analyzing a position or change in position of an autonomous vehicle. For example, the localization systemcan determine position by using one or more of: inertial sensors (e.g., inertial measurement unit(s), etc.), a satellite positioning system, radio receivers, networking devices (e.g., based on IP address, etc.), triangulation or proximity to network access points or other network components (e.g., cellular towers, Wi-Fi access points, etc.), or other suitable techniques. The position of the autonomous vehicle can be used by various subsystems of the sub-control system(s)or provided to a remote computing system (e.g., using the communication interface(s)).

130 110 130 104 110 110 130 110 In some implementations, the localization systemcan register relative positions of elements of a surrounding environment of the autonomous vehicle with recorded positions in the map data. For instance, the localization systemcan process the sensor data(e.g., LIDAR data, RADAR data, camera data, etc.) for aligning or otherwise registering to a map of the surrounding environment (e.g., from the map data) to understand the autonomous vehicle's position within that environment. Accordingly, in some implementations, the autonomous vehicle can identify its position within the surrounding environment (e.g., across six axes, etc.) based on a search over the map data. In some implementations, given an initial location, the localization systemcan update the autonomous vehicle's location with incremental re-alignment based on recorded or estimated deviations from the initial location. In some implementations, a position can be registered directly within the map data.

110 110 110 101 130 In some implementations, the map datacan include a large volume of data subdivided into geographic tiles, such that a desired region of a map stored in the map datacan be reconstructed from one or more tiles. For instance, a plurality of tiles selected from the map datacan be stitched together by the sub-control systembased on a position obtained by the localization system(e.g., a number of tiles selected in the vicinity of the position).

130 130 130 In some implementations, the localization systemcan determine positions (e.g., relative or absolute) of one or more attachments or accessories for an autonomous vehicle. For instance, an autonomous vehicle can be associated with a cargo platform, and the localization systemcan provide positions of one or more points on the cargo platform. For example, a cargo platform can include a trailer or other device towed or otherwise attached to or manipulated by an autonomous vehicle, and the localization systemcan provide for data describing the position (e.g., absolute, relative, etc.) of the autonomous vehicle as well as the cargo platform. Such information can be obtained by the other autonomy systems to help operate the autonomous vehicle.

101 140 102 102 The sub-control system(s)can include the perception system, which can allow an autonomous platform to detect, classify, and track objects and actors in its environment. Environmental features or objects perceived within an environment can be those within the field of view of the sensor(s)or predicted to be occluded from the sensor(s). This can include object(s) not in motion or not predicted to move (static objects) or object(s) in motion or predicted to be in motion (dynamic objects/actors).

140 140 102 104 140 The perception systemcan determine one or more states (e.g., current or past state(s), etc.) of one or more objects that are within a surrounding environment of an autonomous vehicle. For example, state(s) can describe (e.g., for a given time, time period, etc.) an estimate of an object's current or past location (also referred to as position); current or past speed/velocity; current or past acceleration; current or past heading; current or past orientation; size/footprint (e.g., as represented by a bounding shape, object highlighting, etc.); classification (e.g., pedestrian class vs. vehicle class vs. bicycle class, etc.); the uncertainties associated therewith; or other state information. In some implementations, the perception systemcan determine the state(s) using one or more algorithms or machine-learned models configured to identify/classify objects based on inputs from the sensor(s). The perception system can use different modalities of the sensor datato generate a representation of the environment to be processed by the one or more algorithms or machine-learned models. In some implementations, state(s) for one or more identified or unidentified objects can be maintained and updated over time as the autonomous vehicle continues to perceive or interact with the objects (e.g., maneuver with or around, yield to, etc.). In this manner, the perception systemcan provide an understanding about a current state of an environment (e.g., including the objects therein, etc.) informed by a record of prior states of the environment (e.g., including movement histories for the objects therein). Such information can be helpful as the autonomous vehicle plans its motion through the environment.

101 150 150 150 150 The sub-control system(s)can include the planning system, which can be configured to determine how the autonomous platform is to interact with and move within its environment. The planning systemcan determine one or more motion plans for an autonomous platform. A motion plan can include one or more trajectories (e.g., motion trajectories) that indicate a path for an autonomous vehicle to follow. A trajectory can be of a certain length or time range. The length or time range can be defined by the computational planning horizon of the planning system. A motion trajectory can be defined by one or more waypoints (with associated coordinates). The waypoint(s) can be future location(s) for the autonomous platform. The motion plans can be continuously generated, updated, and considered by the planning system.

150 The planning systemcan determine a strategy for the autonomous platform. A strategy may be a set of discrete decisions (e.g., yield to actor, reverse yield to actor, merge, lane change) that the autonomous platform makes. The strategy may be selected from a plurality of potential strategies. The selected strategy may be a lowest cost strategy as determined by one or more cost functions. The cost functions may, for example, evaluate the probability of a collision with another actor or object.

150 150 150 150 150 150 150 150 150 The planning systemcan determine a desired trajectory for executing a strategy. For instance, the planning systemcan obtain one or more trajectories for executing one or more strategies. The planning systemcan evaluate trajectories or strategies (e.g., with scores, costs, rewards, constraints, etc.) and rank them. For instance, the planning systemcan use forecasting output(s) that indicate interactions (e.g., proximity, intersections, etc.) between trajectories for the autonomous platform and one or more objects to inform the evaluation of candidate trajectories or strategies for the autonomous platform. In some implementations, the planning systemcan utilize static cost(s) to evaluate trajectories for the autonomous platform (e.g., “avoid lane boundaries,” “minimize jerk,” etc.). Additionally or alternatively, the planning systemcan utilize dynamic cost(s) to evaluate the trajectories or strategies for the autonomous platform based on forecasted outcomes for the current operational scenario (e.g., forecasted trajectories or strategies leading to interactions between actors, forecasted trajectories or strategies leading to interactions between actors and the autonomous platform, etc.). The planning systemcan rank trajectories based on one or more static costs, one or more dynamic costs, or a combination thereof. The planning systemcan select a motion plan (and a corresponding trajectory) based on a ranking of a plurality of candidate trajectories. In some implementations, the planning systemcan select a highest ranked candidate, or a highest ranked feasible candidate.

150 The planning systemcan then validate the selected trajectory against one or more constraints before the trajectory is executed by the autonomous platform.

150 150 150 140 To help with its motion planning decisions, the planning systemcan be configured to perform a forecasting function. The planning systemcan forecast future state(s) of the environment. This can include forecasting the future state(s) of other actors in the environment. In some implementations, the planning systemcan forecast future state(s) based on current or past state(s) (e.g., as developed or maintained by the perception system). In some implementations, future state(s) can be or include forecasted trajectories (e.g., positions over time) of the objects in the environment, such as other actors. In some implementations, one or more of the future state(s) can include one or more probabilities associated therewith (e.g., marginal probabilities, conditional probabilities). For example, the one or more probabilities can include one or more probabilities conditioned on the strategy or trajectory options available to the autonomous vehicle. Additionally or alternatively, the probabilities can include probabilities conditioned on trajectory options available to one or more other actors.

101 160 160 101 112 150 160 160 112 160 160 112 112 101 To implement selected motion plan(s), the sub-control system(s)can include a control system(e.g., a vehicle control system). Generally, the control systemcan provide an interface between the sub-control system(s)and the platform control devicesfor implementing the strategies and motion plan(s) generated by the planning system. For instance, the control systemcan implement the selected motion plan/trajectory to control the autonomous platform's motion through its environment by following the selected trajectory (e.g., the waypoints included therein). The control systemcan, for example, translate a motion plan into instructions for the appropriate platform control devices(e.g., acceleration control, brake control, steering control, etc.). By way of example, the control systemcan translate a selected motion plan into instructions to adjust a steering component (e.g., a steering angle) by a certain number of degrees, apply a certain magnitude of braking force, increase/decrease speed, etc. In some implementations, the control systemcan communicate with the platform control devicesthrough communication channels including, for example, one or more data buses (e.g., controller area network (CAN), etc.), onboard diagnostics connectors (e.g., OBD-II, etc.), or a combination of wired or wireless communication links. The platform control devicescan send or obtain data, messages, signals, etc. to or from the sub-control system(s)(or vice versa) through the communication channel(s).

101 106 170 170 101 101 170 101 The sub-control system(s)can receive, through communication interface(s), assistive signal(s) from remote assistance system. Remote assistance systemcan communicate with the sub-control system(s)over a network. In some implementations, the sub-control system(s)can initiate a communication session with the remote assistance system. For example, the sub-control system(s)can initiate a session based on or in response to a trigger. In some implementations, the trigger may be an alert, an error signal, a map feature, a request, a location, a traffic condition, a road condition, etc.

101 170 104 170 101 101 After initiating the session, the sub-control system(s)can provide context data to the remote assistance system. The context data may include sensor dataand state data of the autonomous vehicle. For example, the context data may include a live camera feed from a camera of the autonomous vehicle and the autonomous vehicle's current speed. An operator (e.g., human operator) of the remote assistance systemcan use the context data to select assistive signals. The assistive signal(s) can provide values or adjustments for various operational parameters or characteristics for the sub-control system(s). For instance, the assistive signal(s) can include way points (e.g., a path around an obstacle, lane change, etc.), velocity or acceleration profiles (e.g., speed limits, etc.), relative motion instructions (e.g., convoy formation, etc.), operational characteristics (e.g., use of auxiliary systems, reduced energy processing modes, etc.), or other signals to assist the sub-control system(s).

101 150 150 101 The sub-control system(s)can use the assistive signal(s) for input into one or more autonomy subsystems for performing autonomy functions. For instance, the planning systemcan receive the assistive signal(s) as an input for generating a motion plan. For example, assistive signal(s) can include constraints for generating a motion plan. Additionally or alternatively, assistive signal(s) can include cost or reward adjustments for influencing motion planning by the planning system. Additionally or alternatively, assistive signal(s) can be considered by the sub-control system(s)as suggestive inputs for consideration in addition to other received data (e.g., sensor inputs, etc.).

101 160 112 The sub-control system(s)may be platform agnostic, and the control systemcan provide control instructions to platform control devicesfor a variety of different platforms for autonomous movement (e.g., a plurality of different autonomous platforms fitted with autonomous control systems). This can include a variety of different types of autonomous vehicles (e.g., sedans, vans, SUVs, trucks, electric vehicles, combustion power vehicles, etc.) from a variety of different manufacturers/developers that operate in various different environments and, in some implementations, perform one or more vehicle services.

2 FIG. 200 is a block diagram illustrating an example LIDAR system for autonomous vehicles, according to some implementations. The environment includes a LIDAR systemthat includes a transmit (Tx) path and a receive (Rx) path. The Tx path includes one or more Tx input/output ports (e.g., channels), and the Rx path includes one or more Rx input/output ports (e.g., channels). In some implementations, a semiconductor substrate and/or semiconductor package may include the Tx path and/or the Rx path. In some implementations, the semiconductor substrate and/or semiconductor package may include at least one of silicon photonics circuitry, programmable logic controller (PLC), or group III-V semiconductor circuitry.

In some implementations, a first semiconductor substrate and/or a first semiconductor package may include the Tx path and a second semiconductor substrate and/or a second semiconductor package may include the Rx path. In some arrangements, the Rx input/output ports and/or the Tx input/output ports may occur (or be formed/disposed/located/placed) along one or more edges of one or more semiconductor substrates and/or semiconductor packages.

200 101 101 101 101 200 101 1 FIG. The LIDAR systemcan be coupled to one or more sub-control system(s)(e.g., the sub-control system(s)of). In some implementations, the sub-control system(s)may be coupled to the Rx path via the one or more Rx input/output ports. For instance, the sub-control system(s)can receive LIDAR outputs from the LIDAR system. The sub-control system(s)can control a vehicle (e.g., an autonomous vehicle) based on the LIDAR outputs.

202 204 204 206 220 222 208 212 214 224 200 2 FIG. The Tx path may include a light source (e.g., light source), a modulatorA, a modulatorB, an amplifier, and one or more transmitters. The Rx path may include one or more receivers, a mixer, a detector, a transimpedance amplifier (TIA), and one or more analog-to-digital converters (ADCs). Althoughshows only a select number of components and only one input/output channel, the LIDAR systemmay include any number of components and/or input/output channels (in any combination) that are interconnected in any arrangement to facilitate combining multiple functions of a LIDAR system, to support the operation of a vehicle.

202 The light sourcemay be configured to generate a light signal (or beam) that is derived from (or associated with) a local oscillator (LO) signal. In some implementations, the light signal may have an operating wavelength that is equal to or substantially equal to 1550 nanometers. In some implementations, the light signal may have an operating wavelength that is between 1400 nanometers and 1440 nanometers.

202 204 204 206 206 220 220 204 204 The light sourcemay be configured to provide the light signal to the modulatorA, which is configured to modulate a phase and/or a frequency of the light signal based on a first radio frequency (RF) signal (e.g., an “RF1” signal) to generate a modulated light signal, such as by Continuous Wave (CW) modulation or quasi-CW modulation. The modulatorA may be configured to send the modulated light signal to the amplifier. The amplifiermay be configured to amplify the modulated light signal to generate an amplified light signal for transmission via the one or more transmitters. The one or more transmittersmay include one or more optical waveguides or antennas. In some implementations, modulatorA and/or modulatorB may have a bandwidth between 400 megahertz (MHz) and 1000 (MHz).

200 220 222 220 222 230 220 218 222 218 208 222 230 The LIDAR systemincludes one or more transmittersand one or more receivers. The transmitter(s)and/or receiver(s)can be included in a transceiver. The transmitter(s)can provide the transmit beam that it receives from the Tx path into an environment within a given field of view toward an object. The one or more receiverscan receive a received beam reflected from the objectand provide the received beam to the mixerof the Rx path. The one or more receiversmay include one or more optical waveguides or antennas. In some arrangements, the one or more transceiversmay include a monostatic transceiver or a bistatic transceiver.

202 204 208 208 212 The light sourcemay be configured to provide the LO signal to the modulatorB, which is configured to modulate a phase and/or a frequency of the LO signal based on a second RF signal (e.g., an “RF2” signal) to generate a modulated LO signal (e.g., using Continuous Wave (CW) modulation or quasi-CW modulation) and send the modulated LO signal to the mixerof the Rx path. The mixermay be configured to mix (e.g., combine, multiply, etc.) the modulated LO signal with the returned signal to generate a down-converted signal and send the down-converted signal to the detector.

208 212 212 214 212 214 101 224 214 214 212 214 101 218 218 214 224 In some arrangements, the mixermay be configured to send the modulated LO signal to the detector(or detectors). The detectormay be configured to generate an electrical signal based on the down-converted signal and send the electrical signal to a transimpedance amplifier (TIA). In some arrangements, the detectormay be configured to generate an electrical signal based on the down-converted signal and the modulated signal. The TIAmay be configured to amplify the electrical signal and send the amplified electrical signal to the sub-control system(s)via the one or more ADCs. In some implementations, the TIAmay have a peak noise-equivalent power (NEP) that is less than 5 picowatts per square root Hertz (i.e., 5×10−12 Watts per square root Hertz). In some implementations, the TIAmay have a gain between 4 kiloohms and 25 kiloohms. In some implementations, detectorand/or TIAmay have a 3-decibel bandwidth between 80 kilohertz (kHz) and 450 megahertz (MHz). The sub-control system(s)may be configured to determine a distance to the objectand/or measure the velocity of the objectbased on the one or more electrical signals that it receives from the TIAvia the one or more ADCs.

212 250 250 250 250 250 250 218 200 200 The detector(s)may include one or more light-sensitive device(s). The light-sensitive device(s)can be devices that are sensitive to light in their operations. For example, the light-sensitive device(s)may operate differently (e.g., output a different signal type or value) depending upon an amount of light in the ambient environment of the light-sensitive device(s). Examples of light-sensitive devicesinclude, but are not limited to, optical circuitry, photodetectors, optical receivers, and photodiodes. According to example aspects of the present disclosure, the optical isolation of the light-sensitive device(s)can be improved, providing improved performance in detecting the object. Example aspects of the present disclosure may similarly be applied to other substrates and light-sensitive devices that may be present in the LIDAR system, such as light-sensitive devices for feedback or diagnostic systems in the LIDAR system.

3 FIG. 300 300 302 302 304 300 308 306 304 306 308 300 302 depicts a diagram of a substrateexperiencing light leakage according to some aspects of the present disclosure. The substrateincludes photodiodes. The photodiodescan be light-sensitive devices configured to output a signal depending upon an amount of light incident on the photodiode. One or more waveguidescan feed an input optical signal from the upper end of the substrate(e.g., from a light source) to one or more pixels. A junctioncan transfer light between disparate segments or portions of the waveguides. For example, the junctioncan be an edge coupling. The pixelscan emit the light into an environment of a LIDAR system containing the substrateand/or receive reflected light from the environment of the LIDAR system. Additional waveguides can feed the reflected light to the photodiodes. As used herein, “light” refers to energy of a suitable wavelength on the electromagnetic spectrum, which may include visible light and/or non-visible light.

3 FIG. 300 310 310 300 304 300 300 300 312 306 314 308 308 310 312 314 300 300 310 312 314 300 300 302 As depicted in, stray light can enter the environment surrounding the substratein several manners. One such manner is illustrated by stray light. Stray lightdepicts light entering the environment of the substratethat is attributable to misalignment between the waveguidesof the substrateand corresponding waveguides of an additional substrate coupled to the substrate. Even relatively minor misalignments, which may be cost-prohibitive or infeasible to otherwise correct, can contribute to light leakage into the environment of the substrate. Another form of stray lightis attributable to leakage from the junction(e.g., due to misalignments, manufacturing defects, and so on). Yet another form of stray lightis attributable to defects at one of the pixels, such as a misalignment, stray reflected signal, or other unexpected light sourced from the pixel. The stray light,,may not only be present in air above or below the substrate. In some implementations, the substratemay be transparent to light at the wavelengths of the stray light,,, which can allow light to enter the substrateand propagate along the substrate(e.g., by internal reflection) in the direction of the photodiodes.

4 4 FIG.A-D 4 FIG.A 2 FIG. 2 FIG. 400 400 402 404 400 404 402 406 408 400 408 408 406 402 400 200 400 212 250 400 depict cross-sectional views of various substrates according to example aspects of the present disclosure. These substrates can provide improved optical isolation of light-sensitive devices, as described further herein. For instance,depicts a cross-sectional view of an example substrateaccording to some implementations of the present disclosure. The substrateis enclosed in a housing(e.g., a housing of an integrated circuit, a LIDAR system, etc.). A front end of line (FEOL) regioncan define a first side of the substrate. The FEOL regionmay include air, vacuum, or other spacing between the housingand a substrate body. Similarly, a back end of line (BEOL) regioncan define a second side of the substrate. The BEOL regionmay be coupled to additional components of a LIDAR system or other larger system. Additionally or alternatively, the BEOL regionmay define a spacing between the substrate bodyand another side of the housing(not illustrated). The substratemay be included in a LIDAR system, such as the LIDAR systemof. As one example, the substratemay support the detector(s)and/or the light-sensitive device(s)of. Furthermore, in some implementations, the substratemay be or may include a receiver die of a LIDAR sensor system.

410 400 410 404 400 410 400 410 400 410 400 408 400 410 404 408 A light-sensitive devicecan be arranged on the substrate. For instance, in some implementations, the light-sensitive devicecan be arranged on a first side (e.g., the FEOL region) of the substrate. In some implementations, the light-sensitive devicemay be attached or coupled to a surface of the substrate. Additionally or alternatively, the light-sensitive devicemay be embedded within the substrate, The light-sensitive devicemay be arranged closer to a surface corresponding to the first side of the substratethan a second surface corresponding to a second side (e.g., the BEOL region) of the substrate. The light-sensitive devicemay be any suitable light-sensitive device, such as a photodiode, photodetector, optical hybrid, mixer, optical splitter, light source, or any other suitable light-sensitive device. Additional components (not illustrated) may be included in either the FEOL regionor the BEOL region. The present discussion is not intended to exclude substrates having light-sensitive devices at both sides of a substrate, and one of ordinary skill in the art will understand how aspects discussed herein can be extended to any suitable substrate.

400 407 406 407 406 407 400 410 400 2 The substrateman include an oxide layerformed on the substrate body. The oxide layercan be or can include an oxide material, such as silicon dioxide (SiO) or another suitable oxide. The substrate bodycan be or can include a semiconductor layer including any suitable semiconductor material, such as, but not limited to, silicon, a silicon compound, a group III-V semiconductor material (e.g., GaAs), or any other suitable semiconductor material. In some implementations, the oxide layercan be arranged at the first side of the substrate(e.g., the side having the light-sensitive device) and the semiconductor layer can be arranged at the second side of the substrate.

405 410 404 410 405 406 406 406 400 405 406 410 In some implementations, a shielding layercan be arranged above the light-sensitive deviceto prevent stray light from the FEOL regionfrom interfering with the light-sensitive device. While the inclusion of the shielding layermay be beneficial, the substrate body(e.g., the semiconductor layer) may be transparent to light. Therefore, light from various sources (e.g., misalignments, leakages, etc.) can enter the substrate body. Through total internal reflection (TIR), the light can propagate throughout the substrate bodyeven when the sides of the substrateare shielded. Including the shielding layeralone may accomplish little in mitigating the stray light already in the substrate bodyfrom reaching the light-sensitive device.

410 400 412 412 410 400 412 400 412 404 402 406 412 400 407 406 412 412 400 410 412 400 To improve the optical isolation of the light-sensitive device, the substratecan include optical isolation features as described herein. One such optical isolation feature is the blocking trench. The blocking trenchcan be configured to optically isolate the light-sensitive devicefrom light entering the substrate. The blocking trenchcan be an airgap trench, which is filled with a substance occupying an environment of the substrate. For instance, the blocking trenchcan be filled with the same substance as the FEOL region(e.g., the air between the housingand the substrate body). In some implementations, the blocking trenchmay be formed into the substrate, such as by an etch process. For instance, portions of the oxide layerand/or the semiconductor layer (e.g., the substrate body) may be etched away to form the blocking trench. In some implementations, the blocking trenchmay be formed into a first side of the substrate(e.g., a same side as the light-sensitive device.) The blocking trenchcan have one or more sidewalls that are generally planar and/or generally orthogonal to a direction of the sides of the substrate.

412 410 400 412 414 416 418 406 410 410 414 406 400 412 412 410 412 416 418 406 400 400 400 416 418 412 412 416 410 418 412 410 416 412 4 FIG.A The blocking trenchcan be configured to optically isolate the light-sensitive deviceby reflecting light entering the substratethrough total internal reflection. For instance, the blocking trenchcan be arranged such that light (depicted by rays,, and) that enters the substrate bodyis blocked from becoming incident on the light-sensitive deviceand reflected away from the light-sensitive device. As one example, rayillustrates the path of travel of a beam of light entering the substrate bodyparallel to the sides of the substrate. The light will travel until it is incident on the blocking trench, then will be reflected by the sidewalls of the blocking trench. The light can therefore fail to pass to the light-sensitive deviceby reflecting off the sidewalls of the blocking trench. As another example, raysandillustrate light entering the substrate bodyat an angle relative to the sides of the substrate. Because of the total internal reflection between the light and the sides of the substrate, the light will bounce off the sides of the substrateas illustrated by the raysand. As illustrated in, however, the blocking trenchcan be arranged such that the light either hits the blocking trench, as in the case of ray, or passes over the light-sensitive device, as in the case of ray. For instance, the blocking trenchcan be arranged such that light which would normally be incident on the light-sensitive device(e.g., light following the path of ray) can instead be reflected by the blocking trench.

412 406 406 400 406 400 416 410 418 400 412 400 400 412 400 The blocking trenchcan extend a depth D into the substrate body. The depth D may be selected to balance factors such as optical isolation capability (e.g., to cover an increasing spectrum of angles at which the light may enter the substrate body) against structural integrity of the substrate. For instance, the depth D may be selected such that light entering the substrate bodyin a spectrum of angles relative to the direction of the sides of the substrateis either blocked (e.g., as in the case of ray) or passes over the light-sensitive device(e.g., as in the case of ray). In some implementations, the substratecan have a thickness, and a depth of the blocking trenchcan be less than about one half of the thickness of the substrate(e.g., between zero and one half the thickness of the substrate). For instance, in some implementations, the depth of blocking trenchcan be between about 100 micrometers and about 500 micrometers, or between about 20 to about 300 micrometers, or between about 20 to about 200 micrometers. Any suitable depth D, up to the entire thickness of the substrate, may be employed in accordance with example aspects of the present disclosure.

412 406 412 410 406 4 FIG.A 4 FIG.A Although a single blocking trenchis illustrated into block light entering from the left of the substrate body, one of ordinary skill in the art will readily ascertain how multiple or alternative optical isolation trenchesmay be positioned around the light-sensitive deviceto block light from other directions, such as the right of the substrate bodyor in the direction of view relative to the cross-sectional view of.

409 400 409 400 410 409 400 409 409 409 400 409 409 400 400 In some implementations, an antireflection layermay be included on the substrate. For instance, the antireflection layermay be included at the second side of the substrate(e.g., a side opposite the light-sensitive device). The antireflection layermay be formed on the substrate. For example, the antireflection layermay be formed by deposition, film adhesion, or other suitable manner. The antireflection layermay be configured such that light incident on the antireflection layerdoes not experience total internal reflection. For instance, the reflected light off of a surface of the substratehaving the antireflection layermay be reduced, diminished, or eliminated. In this manner, the antireflection layercan provide for mitigating light entering the substrateas it repeatedly reflects off the side of the substrate.

409 412 409 412 400 412 400 400 400 400 410 409 410 410 The combination of the antireflection layerand optical isolation trenchescan be especially advantageous. For instance, the antireflection layercan provide for reduced depth of the blocking trench, therefore improving structural integrity of the substrate. The depth of the blocking trenchcan be selected to block light entering the substrateat less than a certain angle relative to the sides of the substrate. Light that enters the substrateat greater than that angle may reflect off the sides of the substrateseveral times (due to the steep angle) before reaching the light-sensitive device, such that the light is significantly mitigated by the antireflection layerover the multiple reflections. This high-angle light may therefore be weakened before reaching the light-sensitive devicesuch that it is unable to significantly affect the operation of the light-sensitive device.

4 FIG.B 4 FIG.A 4 FIG.A 4 FIG.B 420 420 400 420 400 420 402 404 406 408 410 405 407 409 depicts a cross-sectional view of another example substrateaccording to some implementations of the present disclosure. The substrateis similar to the substrateof. Except where otherwise indicated, components of substratedepicted with the same reference numbers relative to substrateare intended to have the characteristics discussed with regard to. For instance, the substrateincludes a housing, a FEOL region, a substrate body, a BEOL region, and a light-sensitive device. The shielding layer, oxide layer, and antireflection layerare not depicted infor the purposes of illustration, but may nonetheless be included without departing from the present disclosure.

420 422 422 412 412 422 412 422 414 416 418 410 420 4 FIG.A The substrateincludes a blocking trench. The blocking trenchis similar to the blocking trenchof. Unlike the blocking trench, which is an airgap trench, the blocking trenchis a filled trench. The filled trench can have a light-absorbing filling. Instead of reflecting light through total internal reflection as in the case of the airgap trench, the filled trench can directly block or absorb the light incident on the filled trench. For instance, the filled trench may be opaque to the light. The light-absorbing filling can be any suitable light-absorbing filling, such as a metal, a ceramic, an organic compound, or a suspension. One example light-absorbing filling can be a fluid having carbon nanoparticles dispersed in nitrocellulose. The blocking trenchcan absorb light following the path of rayor ray, and light following the path of raycan pass around the light-sensitive device. The use of a light-absorbing filling can provide improved structural integrity of the substraterelative to an airgap trench.

4 FIG.C 4 FIG.A 4 FIG.A 4 FIG.C 440 440 400 440 400 440 402 404 406 408 410 405 407 409 depicts a cross-sectional view of another example substrateaccording to some implementations of the present disclosure. The substrateis similar to the substrateof. Except where otherwise indicated, components of substratedepicted with same reference numbers relative to substrateare intended to have the characteristics discussed with regard to. For instance, the substrateincludes a housing, a FEOL region, a substrate body, a BEOL region, and a light-sensitive device. The shielding layer, oxide layer, and antireflection layerare not depicted infor the purposes of illustration, but may nonetheless be included without departing from the present disclosure.

440 442 444 412 442 440 422 444 442 444 406 410 442 444 410 412 422 442 444 440 442 444 442 444 440 4 FIG.A 4 FIG.B 4 4 FIGS.A andB The substrateincludes an airgap trenchand a filled trench. Similar to the blocking trenchof, the airgap trenchcan be filled with a substance surrounding the environment of the substrate, such as air at the BEOL side. Furthermore, similar to the blocking trenchof, the filled trenchcan be filled with a light-absorbing filling, such as a metal, a ceramic, an organic compound, or a suspension. The trenchesandmay be formed at the second side of the substrate body(e.g., opposite a first side having the light-sensitive device). The trenchesandmay be formed at a farther distance from the light-sensitive devicethan some trenches formed on the first side (e.g., the trenches,of). Furthermore, in some implementations, one or more of airgap trenchand/or filled trenchmay be present on substrate. For instance, more or fewer airgap trenchesand/or filled trenches(including an embodiment having only one of airgap trenchesor filled trenches) may be present on substratewithout departing from the present disclosure.

442 444 406 406 440 406 416 418 440 442 444 440 440 442 444 440 440 442 444 440 412 422 410 410 410 410 4 4 FIGS.A andB The optical isolation trenches,can extend a depth D into the substrate body. The depth D may be selected to balance factors such as optical isolation capability (e.g., to cover an increasing spectrum of angles at which the light may enter the substrate body) against structural integrity of the substrate. For instance, the depth D may be selected such that a significant portion light entering the substrate bodyis blocked (e.g., in the cases of both rayand. In some implementations, the substratecan have a thickness, and a depth of the optical isolation trenches,can be less than about one half of the thickness of the substrate(e.g., between zero and one half the thickness of the substrate). For instance, in some implementations, the depth of optical isolation trenches,can be between about 100 micrometers and about 500 micrometers. Any suitable depth D, up to the entire thickness of the substrate, may be employed in accordance with example aspects of the present disclosure. In some implementations, a greater depth D may be employed for optical isolation trenches on the second side of the substrate(e.g., the trenches,) than on the first side of the substrate(e.g., the trenches,of) to provide for a greater range of One of ordinary skill in the art will readily understand how additional combinations of trenches described herein can be formed without departing from the present disclosure. For example, the first side of the substrate and the second side of the substrate may each have a single trench or multiple trenches, in any combination. As another example, in addition to forming trenches on both sides of the substrate, trenches may be arranged on both sides of the light-sensitive device. The trenches may have various shapes. For example, the trenches may have rectangular, square, V, or half-circular shapes from a cross-sectional view. The trenches may fully enclose or partially enclose the light-sensitive devicefrom a top-down view. For example, the trenches may be cylinders or squares that fully enclose the light-sensitive devicefrom a top-down view, or they may be partial cylinders or squares that partially enclose the light-sensitive devicefrom a top-down view.

5 FIG.A 4 FIG.A 4 FIG.A 5 FIG.A 500 500 400 500 400 500 402 404 406 407 408 410 405 409 depicts a cross-sectional view of another example substrateaccording to some implementations of the present disclosure. The substrateis similar to the substrateof. Except where otherwise indicated, components of substratedepicted with same reference numbers relative to substrateare intended to have the characteristics discussed with regard to. For instance, the substrateincludes a housing, a FEOL region, a substrate body, an oxide layer, a BEOL region, and a light-sensitive device. The shielding layerand antireflection layerare not depicted infor the purposes of illustration, but may nonetheless be included without departing from the present disclosure.

5 FIG.A 500 502 502 500 406 410 502 502 502 410 502 410 404 408 500 500 404 illustrates an example substratehaving an undercut trench. The undercut trenchcan form a cavity in the substrate(e.g., the substrate body) under the light-sensitive device. The cavity can be filled with a light-absorbing filling. The undercut trenchcan directly block or absorb the light incident on the undercut trench. For instance, the undercut trenchmay be opaque to the light. The light-absorbing filling can be any suitable light-absorbing filling, such as a metal, a ceramic, an organic compound, or a suspension. One example light-absorbing filling can be a fluid having carbon nanoparticles dispersed in nitrocellulose. In particular, the undercut trenchcan block light from above and below the light-sensitive device, as well as from at least two lateral directions (e.g., the left and right of the cross-sectional view). In some implementations, the undercut trenchmay be formed such that light in all directions, except for that of a waveguide leading into the light-sensitive device, is blocked. As used herein, terminology such as “above” is used to refer to the direction of the FEOL regionand terminology such as “under,” “below,” or “underneath” is used to refer to the direction of the BEOL regionfor explanatory purposes. This terminology is not intended to invoke any particular arrangement of the substrateitself, such as relative to a LIDAR system, earth gravity, or other arrangement. For instance, the substratemay be mounted in a “flip chip” configuration where the FEOL regionis facing “downwards” (e.g., towards a larger substrate) without departing from the present disclosure.

5 FIG.B 502 502 512 514 512 513 500 515 514 513 515 512 514 513 515 410 410 406 502 520 410 404 illustrates an enlarged view of the undercut trench. The undercut trenchcan be formed of two (or more) filled trenches, including the first filled trenchand the second filled trench. During formation of the filled trench, a corresponding undercut regionis formed by continual etching of the substrate. Similarly, an undercut regionis formed during formation of the filled trench. The undercut regionsandcan have a greater horizontal component (e.g., width) than the respective filled trenchesand. In this manner, the undercut regions,can overlap underneath the light-sensitive deviceand shield the light-sensitive devicefrom light in the substrate body. The undercut trenchcan further include an overfill portionthat shields the light-sensitive devicefrom light in the FEOL region.

Aspects of the disclosure have been described in terms of illustrative implementations thereof. Numerous other implementations, modifications, or variations within the scope and spirit of the appended claims can occur to persons of ordinary skill in the art from a review of this disclosure. Any and all features in the following claims can be combined or rearranged in any way possible. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art. Moreover, terms are described herein using lists of example elements joined by conjunctions such as “and,” “or,” “but,” etc. It should be understood that such conjunctions are provided for explanatory purposes only. Lists joined by a particular conjunction such as “or,” for example, can refer to “at least one of” or “any combination of” example elements listed therein, with “or” being understood as “and/or” unless otherwise indicated. Also, terms such as “based on” should be understood as “based at least in part on. ” As used herein, “about” in conjunction with a stated numerical value is intended to refer inclusively to within twenty percent of the stated numerical value, except where otherwise indicated.

Those of ordinary skill in the art, using the disclosures provided herein, will understand that the elements of any of the claims, operations, or processes discussed herein can be adapted, rearranged, expanded, omitted, combined, or modified in various ways without deviating from the scope of the present disclosure. Some of the claims are described with a letter reference to a claim element for exemplary illustrated purposes and is not meant to be limiting. The letter references do not imply a particular order of operations. For instance, letter identifiers such as (a), (b), (c), . . . , (i), (ii), (iii), . . . , etc. can be used to illustrate operations. Such identifiers are provided for the ease of the reader and do not denote a particular order of steps or operations. An operation illustrated by a list identifier of (a), (i), etc. can be performed before, after, or in parallel with another operation illustrated by a list identifier of (b), (ii), etc.

The following describes the technology of this disclosure within the context of a LIDAR system and an autonomous vehicle for example purposes only. As described herein, the technology described herein is not limited to an autonomous vehicle and can be implemented for or within other systems, autonomous platforms, and other computing systems.